Folding box having diagonally overlapping closing panels



June 6, 1961 R. P. BEMls Erm. 2,987,237

FOLDING BOX HAVING DIAGONALLY OVERLAPPING CLOSING PANELS Filed July 22,1958 4 Sheets-Sheet 2 ROBERT- mss/mss JACK G. Hsefzw@ RICHAR@ C. STENGER INVENTORS #q1-um s W mi ATTORNEY June 6, 1961 R. PL BEMlss Erm.2,987,237

FOLDING Box HAVING DIAGQNALLY OVRLAPPING CLOSING PANELs 4 Sheets-Sheet 3Filed July 22, 1958 www mAc. ma Rey l E m G. w ATTORNEY Julie 6, 1961 R.P. -BEMlss ErAx. 2,987,237

i FOLDING Box HAVING DIAGONALLY OVERLAPPING CLOSING PANELs Filed July22, 1958 4 Sheets-Sheet 4 reos Ere?- f?. BEM/ss Amc cs. HERR/NQ le :cf-fA@ c. STE/v6 E@ JNVENToRs .mug ATTORNEY United States Patent O 2,987,237FOLDING BOX HAVING DIAGONALLY OVER- LAPPING CLOSING PANELS Robert P.Bemiss, Burlingame, Calif., Jack G. Herring, f Portland, Oreg., andRichard C. Stenger, San Carlos,

Calif., assignors to Binns Machine Works, Inc., Redwood City, Calif., acorporation of California Filed July 22, 1958, Ser. No. 750,249

7 Claims. (Cl. 229-40) This invention provides au improved self-lockingfolding box having four diagonally overlapping closing panels, andfurther provides a method of setting up the box blank.

Gluelessly assembled folding boxes having four diagonally overlappingclosing panels are known in principle. The basic blank for a box of thisstyle comprises a centrally located bottom panel to which side wallpanels are articulated-along the four sides. YTop panels extend om theside wall panels. The top panels are roughly of triangular shape andoverlap along marginal areas disposed substantially diagonally withrespect Vto the square or rectangular top surface of the box.

A principalY feature of this sryie of box is that it re;

quires a minimum of stock, since the box is practicallyV ofY single plythickness throughout, except at the areas of overlap.

A principal diculty encountered with forms of known boxes of theaforementioned style is the limited resistance of the box to twisting.Lack of resistance to twisting not only limits Ithe strength of the box,but it may also lead tol a failure of the box closure, since in atwisted box the margin of overlap of the top panels is easily reduced toa point where the four top panels separate. This difficulty may be metto some extent by making the areas of overlap wider, but such a changesacrifices the principal advantage of this style of box which is thesmall amount of board theoretically required.

Certain knownforrns of boxes employ interlocks in which oppositetriangular Vtop panels are locked together at their peak. This form ofinterlock is unsatisfactory because it affords no resistance to twistingsince opposite locked panels are free to slide'substantially parallel toeach other. A box of square top outline is therefore readily twistedinto the shape of a rhombus, and a rectangular box into the shape of arhomboid.

One known form of box employs an interlock between opposite-panels inwhich the apex of one of the top panels is shaped substantially in theform of an arrowhead and inserted into a slit in the opposite top panel.'I'he resulting'engagement leaves the two panels free to slide parallelto one another and provides little, if any, resistance to twisting.

The invention provides an improved form of box and blank in which one ofthe top panels is interlocked with the two adjoining top panels by acentrally disposed lock which alfords a surprisingly high degree oftwist resistance and permits the amount of overlap between the panels tobe held extremely small. The invention further provides a method ofassembling at blanksV into box form and locking three' of the top panelsin such a manner that the 'interlock is relatively loose and easy toengage during the initial phases of the locking operation, butisautomatically tightened when the three top panels are brought intotheir nal position in which the box is also fully squared.

The various features and advantages ofthis invention will appear morefully from the detailed description which follows accompanied bydrawings showing, for the purpose of illustration, a preferredembodiment of the invention. The invention also resides in certain newand original features of construction and the combination of y by-twomain locking cuts 47 and 48 extending from the- Patented June 6,y 1961FIG. 2 is a perspective view of a box in -a condltionr immediately priorto closing;

FIG. 3 is a perspective view of a device for setting up and lockingthree top panels of the box automatically;

FIG. 4 is a perspective view of the device of FIG. 3 showing a partiallyfolded blank engaged by a mandrel; and

FIGS. 5 through 8 illustrate successive phases in the folding andlocking operations resulting in a box structure ready for filling withmerchandise and subsequent closing. In the following description and inthe claims various details will be identified by specific names forconvenience. Ihe names, however,.are intended to be generic in theirapplication. Corresponding reference characters refer -to correspondingparts in the several figures of the drawings.

The drawings accompanying, and forming part of, this specificationdisclose certain specific details of the invention for the purpose ofexplanation of its broader aspects, but it is understood that thedetails may be modified in various respects without departure from theprinciples of the invention and that the invention may be applied to`other structures than the one shown.

The blank A shown in FIG. l may be cut and scored, in multiple, fromlarge sheets or rolls of foldable board, for example paperboard, onautomatic cutting and creasing machines. The blank may be of waxed boardwhich, as is well known, does not lend itself to convenient gluing. Theinvention permits the blank to be formed into box shape entirely byfolding and glueless interlocking.

The blank comprises a bottom panel l11 to which side wall panels 12 and13 are articulated along bottom side fold lines 14 and 15. Lateral toppanels 16 and 17 are articulatedto the side wall panels 12 and 13 alongtop side fold lines 18 and 19.

A back panel 20 is articulated to the bottom panel 11 along a bottomback fold line 21, and a main top panel 22 is articulated to the backpanel along a top back fold line 23. On the opposite side of the blank afront panel 24 is articulated to the bottom panel 11 along a bottomfront fold line 25, and a front top panel 26 is articulated to the frontpanel along a top front fold line 27.

`V The blank areas between the side wall panels and the back and frontpanel, respectively, may be used as corner gussetsin a conventionalmanner, but are shown in the illustrated form of blank as corner aps 28,29, 30 and'. 31, articulated to the side wall panels along Hap foldlines 32, 33, 34 and 35, respectively.

The lateral top panels 16 and 17 are of substantially triangular shapeand are preferably truncated at the tops at 36 and 37 to facilitateassembly. Locking cuts 38 and 39 extend into the lateral panels from theside edgesin a direction toward the truncated apex and form side lockingtabs 40 and 41 pointing away from the respective sides of the main panelinto the board in a direction away from the arrowhead, thereby formingmain locking tabs 49 and 50 to either side of the neck. The tabs 49 and5l)Y point towardsr the arrow point 43.

The base portion S1 of the main panel which lies adjacent the top backfold line 23 is substantially rectangular and is characterized byopposite parallel side edges 52 and 53. Similarly, the front top panel26 has a base portion 54 characterized by parallel side edges 55` and56. The parallel side edges serve to tighten the central interlock ofthe lateral top panels with the main top panel, as will later appear.

The blank A may be shaped into hollow box form either by hand or, moreeconomically, by an automatic forming and locking device in a mannerabout to be described. Y

'Ihe assembly device shown in FIG. 3 comprises a mandrel 57 movablebetween rails 58 and 59. The mandrel is of square bottom outline, thebottom area being just slightly smaller than the area of the bottompanel 11 of the blank. The side surfaces of the mandrel aresubstantially perpendicular at the front and back, but are upwardly andinwardly slanted at the sides, as shown particularly Well in FIG. 5 at60 and 61, to permit the side wall panels of the box blank to be foldedinto a position beyond the vertical for reasons which will hereinafterappear. As a result of the slant of the sides 60 and 61 the lateral topedges 62 and 63 converge rearwardly.

The mandrel is tted with a resilient front bumper- 64 which may bedepressed against the action of springs 65 to lie llush with the frontsurface 66 of the mandrel. As particularly well visible in FIG. 4, themandrel has a recess 67 into which the bumper 64 may be depressed.

The top surface 68 of the mandrel has a leading depressed portion 69 soas to permit the main top panel of the blank to be depressed into aposition slightly below the remainder of the top surface of the plunger.

The mandrel is moved between the rails 58 and 59 by a reciprocable rod70. During its forward stroke the mandrel 57 first encounters a plow orsweep 71 for engaging and folding a blank advanced by the mandrel andmoves thereafter into the space between lateral resilient foldingelements 72 and 73 adapted to fold the side walls of the blank beyondthe 90 degree position with respect to the bottom panel againstithe sidesurfaces 60 and 61 of the mandrel. Further folding and locking elementswill be described in connection with the following explanation of theassembly procedure. Y

At the start of the operation shown in FIG. 4 the blank A is placedunderneath the mandrel 57 with the result that the lateral rails 58 and59 maintain the side wall panel and the lateral top panels 16 and 17substantially vertical. The corner aps 28 and 30 are folded sub.-stantially at right angles with respect to the side wall panels in whichposition they clear the front bumper 64. The main top panel 22 extendsupwardly and is about to be folded down by the plow '7.1 as the mandrelV57 advances. During the assembly operation the blank moveS with the backpanel 20 leading and the front top panel 26 trailing.

FIG. 5 shows the mandrel 57 in an advanced positionY in which the maintop panel 22 is folded over the de pressed top portion 69 of themandrel. The bumper 64 is still fully extended at this phase of theoperation and engages the blank near the toprback fold line 23 alongwhich the main top panel is articulated to the back panel 20.

The lateral top panels 16 and 17 are about to be engaged by the ploW 71which then folds the lateral top panels into a position in whichtheir'truncated apexes overlap, as shown in FIG. 6.

Y Shortly after theleading portion ofV theblank passes the plow 71, thelateral folding elements 72 and Y73 engage` naamw r the side wall panelsof the blank and urge them against the inwardly sloping side surfaces ofthe mandrel 57 so that the overlap of the apexes of the lateral toppanels becomes greater than it is in the nally assembled box. In thisposition the ends of the side locking tabs 40 and r41 are spaced lessthan the ends ofthe main locking tabs 49 and 50.

At this phase of the operation, the back panel 20' of the box which isengaged by the bumper 64 is still forwardly slanted. As a result, thearrowhead 42 is in advance of the side locking tabs 40 and 41.y Duringthe next phase of the assembly operationthe main top panel 22 is engagedby a nger 74 which depresses the main top panel into the depressedportion 69 of the mandrel into a position slightly below the plane ofthe lateral topi panels 16 and 17 so that it will pass underneath thelateral'top panels.

In the position shown in FIG. 7 the extended front bumper of the mandrel(not visible in the figure) maintains the back panel 20 of the box at aforward and upward slant until the back panel engages a transverse bar75. This happens shortly after the point 23 of the arrowhead clears theend of a downwardly extending blade 76` mounted on a transverse bracket77. VAs the mandrel 57 advances from the position shown in FIG. 7V to aposition shown in FIG. 8, the back panel 20'of the box is erected by thetransverse bar 75. 'Ihe bumper is depressed into the recess 67 and thearrowhead 42 moves in a reverse di-Y- rection with respect to themandrel 57. This causes the arrowhead toL ride up on the blade 76 whilethe remainder of the panel 22 including the side locking tabs 40 and 41y(only tab 40V is visible in FIG. 7) slide underneath the lateral toppanels 16, 17. This motion causes the main locking tabs 49 and 50 toengage the side locking tabs 40 and 41.

Shortly after the initial locking engagement takes place,

the parallel side edges 52 and 53 of the, maintop panel,

enter between the side wall panels ofthe box, thereby forcing the sidewall panels as well as the lateral top panels 1-6` and 17' apart into aposition in which the ends of the side locking tabs 40 and 41 are spacedfarther apart than the ends of the main locking tabs 49 and 50. The

spacing of the main locking tabs 49 and 50 may also beY vice. A V-shapedcutout 78 (FIG. 4) provides clearance for the trailing front top panel26 which is stilly at and extended andY lies in substantially the sameplane as theY bottom panel 11. Y

After lling ofthe box with merchandise, the front panel 24 and the fronttop panel 26 are folded into closing position and the front top panel 26lis inserted underneath the lateral top panels 16 and 17. V'I'heparallel side edges S5 and 56 of `the front top panel urge the side wallpanels 12 and 13 apart, thereby further tightening the central lock ofthe top panel assembly byrpulling the side locking tabs 40 and 41 apart.

The locked box is surprisingly strong and rigid, and is particularlytwist resistant. YThe diagonally disposed areas of overlap may be quitenarrow, thereby resulting in great economy of board. lFor example, anoverlap of onequarter of an inch is found sucient in a box having abottom panel measuring 5 x 5 inches.

What is claimed is:

1. A folding box comprising, a bottom panel; two side wall panelsarticulated to said bottom panel along bottom side fold lines; a frontpanel and aback panel articulated to said bottom panel along a bottomfront fold line and a bottom back fold line, respectively, extending atright angles to the side fold lines; and four top panels including twolateral top panels articulated to said side wall panels along top sidefold lines, a front panel articulated to said front wall panel along atop front fold line, and a main top panel articulated to said back panelalong a top back fold line, said top panels being of substantiallytriangular shape, the sides of the triangles overlapping along marginaledge portions, the overlapping portions extending substantiallydiagonally of the top structure, the main panel having an apex portionsubstantially of arrowhead shape, the arrowhead having a point, wings inback of the point, and a reduced neck in back of the Wings, the neckbeing formed by main locking cuts extending from the sides of the mainpanel into the stock in a direction away from the arrowhead forming mainlocking tabs to either side of the neck, said tabs pointing towards thearrow point, each of the lateral panels having side locking cutsextending from a side edge into the panel in a direction towards theapex of the lateral panels forming a side locking tab pointing away fromthe apex, the inner portions of the locking tabs being engaged in thelocked box in a position in which the side locking tabs underlie themain panel and the main locking tabs underlie the side panels, thearrowhead overlying the center of the top structure.

2. A folding box comprising a substantially square bottom panel; twoside wall panels articulated to said bottom panel along bot-tom sidefold lines; a front wall panel and a back wall panel articulated to saidbottom panel along a bottom front fold line and a bottom back fold line,respectively; and four substantially triangular top panels including twolateral top panels articulated to said side wall panels along top sidefold lines, a top front panel articulated to said front wall panel alonga top front fold line, and a main top panel articulated to said backwall panel along a top back fold line, said top panels havingoverlapping marginal edge portions which extend substantially diagonallyof the box top structure, the two lateral panels being truncated attheir apexes suiliciently to prevent overlap at the center of the boxtop structure when the lateral panels are in closing position, the mainpanel having an apex portion substantially of arrowhead shape, thearrowhead having a point, wings in back of the point, and a reduced neckin back of the wings, the neck being formed by cuts extending from thesides of the main panel into the stock in a direction away from thearrowhead and substantially parallel to the sides of the triangle,thereby forming main locking tabs to either side of the neck, said tabspointing towards the arrow point, said main panel comprising asubstantially parallel sided base portion adjacent the top back foldline above which base portion the triangular portion of the panel rises,the lateral panels having locking cuts extending from their side edgesinto the panels in a direction towards the truncated apex of the lateralpanels, said locking cuts forming side locking tabs adapted to beengaged in a hook type engagement with the main locking tabs in aposition in which the side locking tabs underlie the main panel, themain locking tabs underlie the side panels, and the arrowhead overliesthe center of the top structure, and in which the said base portionurges the side wall panels spaced by engagement at the' top side foldlines in a position in which the tips of the side locking tabs arespaced farther apart than the tips of the main locking tabs.

3. A folding box comprising, a bottom panel; two side wall panelsarticulated to said bottom panel along bottom side fold lines; a frontpanel and a back panel articulated to said bottom panel along a bottomfront fold line and a bottom back fold line, respectively, extending atright angles to the side fold lines; and four top panels including twolateral top panels articulated to` said side wall panels along top sidefold lines, a front top panel articulated to said front wall panel alonga top front fold line, and a main top panel articulated to said backpanel along a top back fold line, said top panels being of substantiallytriangular shape, the sides of the triangles overlapping along marginalportions, the overlapping portions extending substantially diagonally ofthe top structure of the closed box, the main panel having an apexportion substantially of arrowhead shape, the arrowhead having a point,wings in back of the point, and a reduced neck in back of the wings, theneck being formed by main cuts extending from the sides of the mainpanel into the stock in a direction away from the arrowhead forming mainlocking tabs to either side of the neck, said tabs pointing towards thearrow point, the lateral panels having locking cuts extending from theirside edges into the panels in a direction towards the apex of thelateral panels forming side locking tabs pointing away from therespective apex, the locking cuts being so located with respect to themain cuts that an internal portion of each main cut coincides with aportion of a locking cut in a lateral panel, when the panels are inmarginally, overlapping box closing position for interengagement of themain locking tabs with said side locking ta-bs in hook-type engagement.

4. A folding box comprising, a bottom panel; two side wall panelsarticulated to said bottom panel along bottom side fold lines; a frontpanel and a back panel articulated to said bottom panel along a bottomfront fold line and a bottom back fold line, respectively, extending atright angles to the side fold lines; and four top panels including twolateral top panels articulated to said side wall panels along top sidefold lines, a front top panel articulated to said front wall panel alonga top front fold line, and a main top panel articulated to said backpanel along a top back fold line, said top panels being of substantiallytriangular shape, the sides of the triangles overlapping along marginalportions, the overlapping portions extending substantially diagonally ofthe top structure of the closed box, the main panel having an apexportion substantially of arrowhead shape, the arrowhead having a point,wings in back of the point, and a reduced neck in back of the wings, theneck being formed by main cuts extending from the sides of the mainpanel into the stock in a direction away from the arrowhead forming mainlocking tabs to either side of the neck, said tabs pointing towards thearrow point, the lateral panels having locking cuts extending from theirside edges into the panels in a direction towards the apex of thelateral panels forming side locking tabs pointing away from therespective apex, the locking outs being so located with respect to themain cuts that an internal portion of each main cut in the main toppanel coincides with a portion of a side locking cut in a lateral panelwhen the panels are in marginally overlapping, box closing position, thetips of the side locking tabs being spaced farther apart than the tipsof the main locking tabs.

5. A folding box as set vforth in claim 4 in which the lateral panelsare truncated suiiciently so as not to overlap in the position in whichthe main panel and the lateral panels are in box closing position inwhich also the main locking tabs underlie the lateral panel and the sidelocking tabs underlie the main panel in locking interengagement of themain panel with the lateral panel.

6. A folding box as set forth in claim 4 in which the main top panelcomprises a substantially parallel-sided rectangular base portionadjacent the top back fold line above which base portion the triangularportion of the main panel rises, the distance between the parallel sidesof the base portions being substantially equal to the distance betweenthe bottom side fold lines.

7. A folding box as set forth in claim 4 in which both the main toppanel and the front top panel comprise a References Cited in the le ofthis patent UNITED STATES PATENTS Arneson ..f- D ec. 4,' 1956 BoldingMar. 5, 1,957 Sparks May 1431957 Klein Feb. 25, 1958

